With the recent development of wireless communication technology, antenna devices are embedded in various electronic apparatuses and their use is increasing rapidly.
The electronic apparatus having the built-in antenna device performs various additional functions by communicating with other electronic apparatuses using other built-in antenna devices.
For example, data transmission is performed between antenna devices built in a smart device, and data transmission/reception is performed using short-range communications or Wi-Fi communications between smart terminals, for example.
In recent years, more advanced forms of antenna devices have been used to transmit and receive power wirelessly. In other words, although a technique of receiving power using a power line has been mainly used in the past, development of a wireless power transfer (WPT) technology capable of receiving power by radio has been actively developed.
Such a wireless power transmission technology is a technology of enabling an antenna device built in an electronic apparatus to receive wireless power in the form of electromagnetic induction or electromagnetic resonance and to supply power anytime and anywhere wirelessly without a power line such as an electric wire or cable.
Korean Patent Application Publication No. 10-2007-0099195 discloses a double-sided antenna with a micro strip structure, which includes: a circuit region outside a substrate; upper and lower dielectric regions in which metal is removed from upper and lower sides of the substrate; and upper and lower antenna patterns respectively formed in the upper and lower dielectric regions.
Korean Patent Application Publication No. 10-2007-0099195 has an advantage that one of the upper and lower antennas respectively formed on both sides of the substrate has a relatively good propagation environment, and the antenna having the relatively good propagation environment may be selectively used. However, there is a disadvantage that the double-sided antenna cannot be realized with one antenna because the upper and lower antennas are not connected with each other, and a switch for selectively switching the upper and lower antennas is separately provided and thus the double-sided antenna is therefore unsuitable as a recent antenna device for wireless charging.